Visual Six Sigma: Making Data Analysis Lean

8.2. Framing the Problem

To frame the problem, Carl and his team develop a formal project charter. Additionally, they obtain customer input that directs them to focus on two critical process characteristics, melt flow index and color index.

8.2.1. Developing a Project Charter

During their first team meeting, Carl and his team members draw a high-level process map (Exhibit 8.3). They also decide to review yield data from both the polymer and molding plants to confirm the size and frequency of the problem.

Figure 8.3. High-level Process Map of White Polymer Molding Process

There have been many arguments about white polymer quality. Although there is a polymer specification, the molding plant has long suspected that it does not fully reflect the true requirements of their process. After a long discussion, the team agrees on the following Key Performance Indicator (KPI) definition for the project:

Daily yield, calculated as the weight of good polymer divided by the weight of total polymer produced.

Good polymer is polymer that can be successfully processed by the molding plant.

Total polymer produced will include product that fails to meet the polymer plant specifications, plus any polymer that, although meeting polymer plant specifications, is subsequently scrapped or rejected in the molding plant.

Carl collects some historical data on daily yield and imports it into a data table ...